The present invention is directed toward a vibratory hearth and, more particularly, toward such a hearth which is used in a thermal processor or incinerator for treating or disposing of waste materials.
Non-hazardous and hazardous waste materials may consist of solids and/or liquids and are of wide and various compositions. With the proper retention and placement of materials in a thermal processor or incinerator, such materials can be processed safely. However, if the material bypasses the complete process due to either physical state or physical shape, the material is not safely or completely processed.
Devices have been proposed in the past for safely treating or incinerating waste materials. U.S. Pat. No. 3,592,150, for example, is directed toward a method and device of incinerating viscous liquids and includes an inclined hearth onto which the liquid is introduced. However, the hearth is stationary and accordingly a rake must be constantly utilized to move and remove the ash.
A significant advance was taught in U.S. Pat. Nos. 3,791,316 and 3,841,242 wherein air is introduced from beneath the hearth and the hearth is inclined downwardly and is also vibrated. While these patents describe systems that are useful for burning solid materials, they are not particularly useful for liquids.
The stirring action of a rotary kiln has made it popular in waste incineration applications. The rolling action exposes the bottom of the unburned waste material to the combustion air. U.S. Pat. No. 4,793,269 has further improved on this technology by proposing a rotary kiln wherein underfire combustion air is introduced into the kiln.
In forward-inclined hearths or kilns a liquid can transverse the treatment area much quicker than the solid components. Also, a shape that can easily roll will traverse the treatment area much quicker than flat objects. In either of these cases, when treatment time at a particular temperature is important, bypassing the treatment area can result in ineffective treatment. For applications where the feed stream is variable and/or mixed, none of the hearths of the prior art can satisfactorily deal with the same. Nor has the prior art satisfactorily dealt with the removal or accumulation of ash that falls down through air holes in the grate.